1. Field of the Invention
The present invention relates to an antenna and a communication device including the same.
2. Discussion of Related Art
Any device that performs wireless communication requires an antenna. The antenna is not operated in all frequency bands but is resonated only in a fixed frequency band, and therefore, in order to provide a specific communication service in a communication device, the antenna should be designed to be resonated in a frequency band for the specific communication service.
However, in recent years, according to the advent of various communication service bands, an operating frequency band required for the antenna has been gradually increased. That is, in order for a single communication device to cover various communication services, the bandwidth of the antenna may be expanded or the antenna may be designed to be operated in multiple bands.
In addition, according to the miniaturization of the communication device, an inverted F-type antenna has been widely used in a compact device such as a mobile communication terminal, a smart phone, or the like. This is because, using the inverted F-type antenna, it is possible to cover a required existing service band and obtain appropriate excellent performance.
However, there are the following problems in the case of using the inverted F-type antenna.
First, in order for the inverted F-type antenna to be designed to be operated in multiple bands, a change is given to a pattern shape and methods of designing the inverted F-type antenna are different for each antenna designer, and therefore there is a huge variety of the pattern shapes of the completed antenna. That is, there is no established single design method.
Second, in order for the inverted F-type antenna to be included in the communication device, a ground area to exist below the antenna should be removed. Otherwise, the performance of the antenna is not properly exhibited. However, when partially removing the ground area owing to a space for the antenna, there is a problem in that a display area cannot be expanded in the partially removed ground area. This is because the ground area should exist below the display area. In other words, as shown in (a) of FIG. 1, in order for a display area 2 of a communication device 1 to be expanded to the entire surface, a ground plane should be formed over the entire surface, and therefore there is no space in which the inverted F-type antenna is formed. As shown in (b) of FIG. 1, in order to ensure a space 3 in which the inverted F-type antenna is formed in the communication device 1, the ground plane should be partially removed, and therefore there is a problem in that the display area 2 is reduced. Because of this dilemma, conventionally, a communication device having the structure shown in (b) of FIG. 1 was manufactured in most cases.
Thus, in recent years, a simple and clear antenna design method has been required, and development of an antenna that can exhibit excellent performance even in a full ground state in which the ground plane is not removed has been highlighted as an urgent task.